It is well recognized that the functional recovery of an injured nerve depends on the cellular environment. A number of attempts have been made to control neural repair using entubulation of severed ends to guide new tissue regeneration, using various materials, but without great success. Conversely, collagen-based materials for guided tissue regeneration have proven successful in a number of applications. In order to facilitate nerve regeneration, collagen-based tubular guiding conduits were designed and prepared to serve as repair devices for peripheral nerve damage. The phase I study was focused on 1) fabrication techniques to develop well characterized type I collagen tubes; 2) assay methods to characterize and quality the collagen tubes, in order to ensure the safety and efficacy of the device; 3) short term in vivo studies in rodents; 4) initiation of long term in vivo studies on rodents and primates having short gaps (4 mm), with initial assessments of neural repair made via electrophysiology measurements. The short term in vivo studies and the initial results from the long term studies have shown neural recovery that was equivalent or better than autograft of transected peripheral nerves. Phase II is intended to continue the long term electrophysiology assessments of primates having 4 mm repair sites, as well as initiating a primate study for 2 cm and 5 cm gap repair of the median nerve.